FDTD investigation of higher order mode leakage from three dimensional microstrip line structures

Electromagnetic field leakage phenomena associated with the first higher order mode of an asymmetrically fed microstrip line structure is investigated by using the FDTD method. From the obtained scattering parameters and loss factor of the three-dimensional microstrip line structure, leakage properties of the first higher order mode at different frequencies are made clear, and they confirm the predictions of the two-dimensional transmission line analysis. Experimental measurements are implemented and the measured data are in favorable agreement with the simulated results.